The Consequences of Metamorphosis on Salamander (Ambystoma) Locomotor Performance

Radical shifts in morphology and ecology of salamanders during metamorphosis affect many aspects of their life history. We quantify the effects of metamorphosis on burst speed and endurance capacity on a large sample of Ambystoma californiense. Locomotor performances are highly repeatable within metamorphic stages but change dramatically between larval and postmetamorphic stages. For burst speed, larvae are twice as fast as metamorphosed aquatic animals, and metamorphosed terrestrial salamanders are even slower. However, mean endurance of terrestrial animals is significantly greater than for either aquatic stage. Repeatabilities of burst and of endurance between metamorphic stages are zero, suggesting that they are under separate physiological control. In addition, correlations between burst and endurance, both within and among metamorphic stages, are zero. Metamorphosis seemingly decouples locomotor performance in different environments and promotes increased flexibility for organisms with complex life cycles.